After receiving these packages, he said he and his wife will from now on order their seeds locally.
The federal inspection agency said evidence indicates the packages are part of a “brushing scam” in which sellers send unsolicited items in hopes of increasing sales.
Although the risk is low for some nefarious outcome, like introducing an exotic species in the United States or some form of biological warfare, recipients of the mailings should not plant the seeds, said Art Gover, a plant science researcher at Penn State University.
These seeds can be troublesome because they can introduce problematic weeds and diseases, he said.
Lisa Delissio, a professor of biology at Salem State University in Massachusetts, said if any of the unidentified seeds turned out to be invasive species, they could displace native plants and compete for resources and cause harm to the environment, agriculture or human health.
Bernd Blossey, a professor in the department of natural resources at Cornell University in Ithaca, N.Y., said he received a few calls from worried recipients of the seed packets.
“Obviously planting rosemary or thyme in your garden isn’t something that will endanger our environment,” he said. “But there may be other things in there that have not been identified yet. Any time you gain something unknown, my suggestion is burning them, not even throwing them in the trash.”
Gardeners have been responsible for introducing invasive plant species in the past, and nurturing them with a green thumb, including the butterfly bush, Japanese knotweed and some ornamental grasses, Professor Blossey said.
“Who knows who’s behind it or what’s behind it?” he said. “I think there may be more to the story.”
Marie Fazio and Christina Morales contributed reporting.